Australia recently announced that it would roll out the fourth dose of Covid-19 vaccines to its most vulnerable population in April.
The Australian Health Minister Greg Hunt had confirmed to media on Friday (March 25) that a second booster shot will be offered from April 4 to people who had their previous booster shot at least four months ago and are over 65 years, indigenous Australians over 50, people with disability or severely immunocompromised.
On Thursday (March 24), Director-General of Health Dr Ashley Bloomfield said he was waiting for advice from the technical advisory group regarding the need for the fourth dose. He said he is expected to get the advice in a week. “I am approaching the decision around whether a fourth dose was needed from the point of view that, is there a good reason not to offer a fourth dose if there is evidence of waning immunity? And there is some evidence of that. So we would be offering the fourth dose to our vulnerable communities, especially older people," Bloomfield said.
He said information around a fourth dose was emergent and "quite scanty". A fourth dose is currently offered to all adults in Israel and is also being rolled out in the UK from April to older people, immunocompromised and care home residents.
"It will really be looking at what other countries are doing," Bloomfield said.
We spoke to Covid-19 experts in New Zealand to determine if NZ should follow the Australian path and introduce a fourth vaccine dose.
Dr.Nikki Turner, Medical Director, The Immunisation Advisory Centre and Professor (hon), Department of General Practice and Primary Health Care, University of Auckland for NZ the consideration is who would benefit from the extra booster dose. She says, “NZ is currently actively considering the issue of who would benefit from an extra booster dose of a Covid-19 vaccine. It is clear that immunity does wane over months. It lasts longer as a protection against severe disease than against mild disease, but it still does wane.
“From the accumulating international data it does suggest that higher risk groups are going to need an extra booster dose for further protection - and initially that would likely be older people and others with significant medical issues that put them at risk of more severe Covid-19 disease. There is no evidence that younger and healthier people at this point need a further booster dose.”
Michael Baker, Epidemiologist and Professor, Department of Public Health, University of Otago, also shares Turner’s views and feels that a fourth dose should be offered to those who are most vulnerable to severe illness from Covid-19.
Baker says, "Immunity wanes over 3-6 months following the second and third dose of Pfizer vaccine. A fourth dose is expected to boost that immunity, so I think it should be offered to those who are most vulnerable to serious illness from Covid-19.
Helen Petousis-Harris, Vaccinologist and Associate Professor, Dept of General Practice and Primary Health Care, University of Auckland, also feels that a second booster might be an option for high-risk people. She says, "A fourth dose might be recommended for high-risk groups. There is little gain for most people.”
So, should it be made compulsory for all?
Baker feels that it should not be made compulsory. "I don't think this further dose should be compulsory except perhaps for groups where a vaccine mandate applies (notably health care workers)," points out Baker,
Petousis-Harris shares the same sentiment and says, "It is highly unlikely to be compulsory.”
Will there be any adverse impact of the fourth dose?
Baker responds, "I am not aware of any adverse impacts of a fourth dose. Many people receive an annual influenza vaccination for many years, so repeated vaccination is a well-established method for maintaining immunity."
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